How badly do South Koreans want nuclear weapons? The 2025 Asan Poll found a record 76.2% public support for acquiring an indigenous nuclear weapons capability and 66.3% support for the redeployment of U.S. tactical nuclear weapons to the Korean Peninsula. One of the main critiques of such findings is that the headline figures misrepresent the public’s true commitment to nuclear armament or redeployment. That is, support is expected to dramatically drop when people are asked to consider the potential costs of acquiring nuclear weapons. This Asan Issue Brief introduces the results of a series of conditions-based questions to test the robustness of South Korean public commitment to enhanced nuclear options. The five conditions include a willingness to face international sanctions, risk the withdrawal of U.S. forces from the Korean Peninsula, build storage facilities and conduct nuclear tests, increase defense cost-sharing with the United States, and host tactical nuclear weapons in their city or province.

The Issue Brief finds that a majority of the South Korean public is now committed to both nuclear armament and nuclear redeployment even in the face of four out of five potential cost conditions due to record-high threat perceptions and concerns about the U.S. security commitment. The high headline support for nuclear armament (76.2%) and nuclear redeployment (66.3%) means that even substantial drops in support no longer fall below majority support. However, the South Korean public is most sensitive to specific and tangible potential costs that have a direct impact on them, including hosting deployment of weapons as well as storage and testing facilities in their locality, whereas abstract and unspecified costs only have a modest impact on commitment. While indigenous nuclear armament appears to enjoy higher levels of support over nuclear redeployment, rather than being indicative of public preference, we hypothesize that more specific and tangible cost conditions would quickly erode the headline figure given indigenous nuclear armament will involve much higher costs, potentially involving all five conditions occurring simultaneously, than nuclear redeployment within an alliance framework. In conclusion, our results suggest that public sentiment represented by the headline figures is best understood as a reflection of dissatisfaction with current deterrence measures.

The Issue Brief proceeds as follows. First, it explains the failure of existing ROK-U.S. extended nuclear deterrence measures to reassure the South Korean public, whose threat outlook is more severe than ever. It shows that alternative nuclear options have record levels of support, including indigenous nuclear armament and the redeployment of U.S. nuclear weapons. Second, it reviews the three conditions used to test the strength of public commitment to indigenous nuclear armament, including a willingness to face international sanctions, risk the withdrawal of U.S. forces, and build storage facilities and conduct nuclear tests. Third, it reviews the two conditions for nuclear redeployment, including a willingness to increase defense cost-sharing with the United States and host tactical nuclear weapons in their city or province. Fourth, it discusses policy implications and offers recommendations, including about the strength of headline support, the role of specific and tangible costs, the viability of nuclear redeployment over indigenous armament, and the need for further survey experiments and focus group interviews to identify the specific pathways for maintaining support for stronger nuclear options.

Introduction

1. Rising Insecurity, Falling Credibility, and Nuclear Options

2. Public Support for Indigenous Nuclear Armament
Condition 1. International sanctions
Condition 2. Withdrawal of U.S. forces
Condition 3. Build sites and conduct tests

3. Public Support for Redeployment of U.S. Nuclear Weapons
Condition 4. Increase defense cost-sharing
Condition 5. Host in own city/province

4. Policy Implications and Recommendations

Conclusion